Age & Gap Problems
Age puzzles look hard because the numbers keep changing — but one thing never moves. Try each problem first, then watch the Constant Crew reveal the trick.
1 Explore — try these first
Age problems feel tricky because the numbers keep changing as everyone grows up. But there is one thing that never changes — and once you learn to spot it, every puzzle below cracks open.
Try each problem first. Print the problem set, give it a real attempt on paper, and only then scroll down to watch how the Constant Crew solves it. The struggle is the part that makes it stick.
★ · The Gap Never Closes
A dad is 30 years old and his daughter is 6. Every year they both have a birthday. How much older than his daughter is the dad this year? What about in five years? What about three years ago?
L0 · Slide the Whole Timeline
A puppy named Pebble is 2 years old. Her big brother dog, Bruno, is 9. How old will each of them be in five years — and what is the gap then?
L1 · Meet in the Middle
Two cousins’ ages add up to 30. One cousin is 4 years older than the other. How old is each cousin?
L2 · The Gap in Parts
Nadia is 4 times as old as her little cousin Theo, and 15 years older than him. How old is each of them right now?
L3 · Two Equal Hops
Leo is 9 years old. His grandpa says, “When you are as old as I am right now, I will be 67.” How old is Grandpa today?
L4 · When Does the Multiple Hit?
Theo is 40 years old and his daughter Lily is 10. In how many years will Theo be exactly twice as old as Lily?
L5 · Age Detective
A family of four — mum, dad, big sister, and a baby — have ages that add up to 80 now. Five years ago, their ages added up to 63. How old is the baby?
L6 · Two Snapshots, One Gap
Maria is 3 times as old as her little brother. In four years, she will be only twice as old as him. How old is each of them right now?
L7 · Digits & Ages
A grandmother and her granddaughter’s ages use the same two digits, just flipped. The two ages add up to 88, and Grandma is 54 years older. How old is each?
L8 · Average Age
A family of five has an average age of 24 right now. In six years, what will their average age be? And if a 54-year-old grandparent joins today, what is the family’s average then?
2 Learn — watch the solutions
Gave each one a real try? Now watch the trick. (Stuck is fine — that's the point.)
★ · The Gap Never Closes
Peek the trick — The Gap Never Closes
The “times older” keeps changing, but the difference between two ages stays exactly the same forever. That frozen gap is the thing to hold onto in every age problem.
L0 · Slide the Whole Timeline
Peek the trick — Slide the Whole Timeline
“In N years” slides both ages the same amount along one timeline, so the gap between them does not change.
L1 · Meet in the Middle
Peek the trick — Meet in the Middle
Halve the sum to find the average, then step out by half the gap to each side.
L2 · The Gap in Parts
Peek the trick — The Gap in Parts
Turn “times as old” into equal parts; the known gap divided by the number of parts gives one part.
L3 · Two Equal Hops
Peek the trick — Two Equal Hops
The sentence hides two equal jumps along the number line, because each jump is one age gap.
L4 · When Does the Multiple Hit?
Peek the trick — When Does the Multiple Hit?
The gap is frozen; at the target moment it equals one “part,” which tells you exactly which year it happens.
L5 · Age Detective
Peek the trick — Age Detective
A group’s total age should fall by people × years; when it doesn’t fall enough, someone wasn’t born yet — and the missing drop is their age.
L6 · Two Snapshots, One Gap
Peek the trick — Two Snapshots, One Gap
Two “times as old” facts describe two different moments; the same constant gap bridges both pictures.
L7 · Digits & Ages
Peek the trick — Digits & Ages
For reversed two-digit ages, the sum is 11 × the digit sum and the gap is 9 × the digit difference; finish with Meet in the Middle.
L8 · Average Age
Peek the trick — Average Age
Total = average × count. When time passes the average climbs by the elapsed years; when a member joins, recount over the new total.
3 Master — practice on your own
Print the practice sheet and solve without the videos. Check your answers at the back — if one is wrong, the answer key names the trick so you know exactly which video to rewatch.
Download fresh practice problems PDF
